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1 files changed, 77 insertions, 0 deletions

diff --git a/src/input-reader.hpp b/src/input-reader.hpp
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+/*
+ * Copyright (c) 2020-2021 Vasile Vilvoiu <vasi.vilvoiu@gmail.com>
+ *
+ * specgram is free software; you can redistribute it and/or modify
+ * it under the terms of the MIT license. See LICENSE for details.
+ */
+#ifndef _INPUT_READER_HPP_
+#define _INPUT_READER_HPP_
+
+#include <istream>
+#include <mutex>
+#include <optional>
+#include <thread>
+#include <vector>
+
+/*
+ * Input reader base class
+ */
+class InputReader {
+protected:
+    std::istream * const stream_;
+    const std::size_t block_size_bytes_;
+
+public:
+    InputReader() = delete;
+    InputReader(const InputReader&) = delete;
+    InputReader(InputReader&&) = delete;
+    InputReader & operator=(const InputReader&) = delete;
+
+    InputReader(std::istream * stream, std::size_t block_size_bytes);
+    virtual ~InputReader() = default;
+
+    virtual bool ReachedEOF() const = 0;
+    virtual std::optional<std::vector<char>> GetBlock() = 0;
+    virtual std::vector<char> GetBuffer() = 0;
+};
+
+/*
+ * Synchronous input reader
+ */
+class SyncInputReader : public InputReader {
+public:
+    SyncInputReader(std::istream * stream, std::size_t block_size_bytes);
+
+    bool ReachedEOF() const override;
+    std::optional<std::vector<char>> GetBlock() override;
+    std::vector<char> GetBuffer() override;
+};
+
+/*
+ * Asynchronous input reader
+ */
+class AsyncInputReader : public InputReader {
+private:
+    /* buffer where we read up until one block */
+    volatile char *buffer_;
+    volatile std::size_t bytes_in_buffer_;
+
+    /* mutex for accessing buffer */
+    std::mutex mutex_;
+
+    /* thread for reading from input stream */
+    std::thread reader_thread_;
+    volatile bool running_;
+
+    void Read();
+
+public:
+    AsyncInputReader(std::istream * stream, std::size_t block_size_bytes);
+    ~AsyncInputReader() override;
+
+    bool ReachedEOF() const override;
+    std::optional<std::vector<char>> GetBlock() override;
+    std::vector<char> GetBuffer() override;
+};
+
+#endif